Evaluation of sudomotor function in diabetes using the dynamic sweat test

Area of Science:

• Autonomic Nervous System Research
• Diabetic Complications
• Clinical Physiology

Background:

• Sudomotor function assessment is crucial for diagnosing autonomic disorders.
• Existing tests measure whole-body sweat output or localized sweat drops at a single time point.
• The dynamic sweat test (DST) was developed to simultaneously measure sweat gland density, active gland distribution, and sweat rate.

Purpose of the Study:

• To evaluate the utility of the dynamic sweat test (DST) in assessing sudomotor function in asymptomatic diabetic subjects.
• To compare sudomotor function between diabetic individuals and healthy controls using the DST.

Main Methods:

• The DST was applied to the forearm and distal leg of 14 diabetic subjects and 14 controls.
• Pilocarpine-induced sweating was visualized using a digital video camera and a transparent tape with cornstarch.
• Key metrics evaluated included sweat gland density (per cm(2)), sweat output per gland (nL/min), and sweat output per skin area.

Main Results:

• Diabetic subjects showed significantly reduced sweat gland density and mean sweat output per gland and per skin area in the lower limb compared to controls (p < 0.05).
• Forearm sweating measurements did not reveal significant differences between diabetic subjects and controls.
• These findings suggest localized sudomotor deficits in the lower extremities of individuals with diabetes.

Conclusions:

• The dynamic sweat test (DST) is a practical and informative method for evaluating sudomotor function.
• DST can detect subtle sudomotor changes indicative of early-stage diabetic neuropathy.
• This test offers a valuable tool for the early diagnosis and management of diabetic autonomic dysfunction.